Adds a lot of Custom Mutations created by me and others.
The main-menu has been edited so all Mutations can be created via lobbies, and can be played online at anytime. To play Custom Mutations online, they'll have to be played via a Local Server.
If you have my Singleplayer Enabler mod (linked below), you can play 4-player Mutations in Singleplayer!

This mod is essentially adding on to what Valve already started with "mutations"... adding more game modes and such.
A great way to make the game more challenging without silly over modified servers or map authors abusing the director in maps.

- Super Interactive Menu
- Dozens of varieties and ways to play
- Incredibly challenging
- Super useful to use as a training
- He entered my favorites list

Cons

- Absolutely nothing against this piece of art.

This is perhaps the best mod mutation that played in L4D2. The huge plethora of options are incredible. Each with its characteristic, challenge and goal. I was very happy to have found this mod, he left my very best game. Congratulations and thank you for provide hours of fun.
p.s.: downloaded from their facebook page

The last duo on Earth mutations
A lot of L4D2 achievements can be unlocked using the training mutations and/or the realism ones
Jimmy Gibbs!
It is a guideline for new coming L4D2 add-on creators
Tons of other pros

Cons

Few mutations are so hard that I could not advance more than few meters from the starting safe area.

Keep your installation up to date, because - I am sure - you have this mutations mega-pack installed.